Fuel combustion process and apparatus



T. M. G. SIMMONS 2,769,411

FUEL. COMBUSTION PROCESS AND APPAR'ATUS 2 Sheets-Sheet l Nov. 6, 1956Filed Nov. 6, 1951 INVENTOR. TORSTEN MAGNUS GEORG slMMoNS HIS ATTORNEYS.

Nov. 6, 1956 T, M. G. SIMMONS FUEL. COMBUSTION PROCESS AND APPARATUS 2Sheets-Sheet 2 Filed NOV. 6, 1951 INVENTOR. TORSTEN MAGNUS GEORG s|MMoNsHISz ATTORNEYS.

United States Patent l FUEL COMBUSTION PROCESS APPARATUS Torsten MagnusGeorg Simmons, Norrkoping, Sweden,

assignor, by mesne assignments, toRosenblad Corporation, New York, N.Y., a corporation of New York Application November 6, 1951, Serial No.255,097

2 Claims. (Cl. 110-28) This inventionfrelates to combustion in acombustion chamber of the so called Whirl chamber type having anapproximately circular cross section, and in which air and combustiongases containing solid components are caused to stream through thechamber in a helical path along the interior surface of the chamber inthe direction towards a main exhaust through which said gases are discharged so as to heat the heating surfaces of a boiler for instance.Conditions of this kind arise in the combustion of fuel' introduced intothe combustion chamber in the form of powder or lumps, but can alsoarise if a hydrous liquid fuel, for instance waste sulphite lyeevaporated to contain 50--60% of dry substances, is injected into thechamber in the for-m of a spray or drops. The drops will then be ignitedonly after having dried to powder, whereupon-'the combustion processwill take place in the same way, as if the fuel had been initiallyintroduced into the chamber in such a pulverized form, so that thecombustion of the dried particles Will proceed while they are beingcarried on by the whirl of air and gases. As far as possible losses ofparticles of fuel through the main exhaust should be prevented.Especially When burning fuels having large contents of ashes it is alsoimportant to prevent that large quantities of ashes proceed that Way andform coatings on the heating surfaces thus necessitating frequentcleaning of said surfaces.

The main object of the invention is to remove continuously such solidsubstances from the combustion chamber, before being discharged throughthe main exhaust.

A further Yobject of the invention is to utilize to this purpose thecharacteristicl feature of the aforesaid type of combustion chamber,namely that owing to the iniuence of the centrifugal force thelayer ofthe combustion gas Vwhirl moving adjacent tothe interior Wall surface ofthe'chamber will be enrichedl or concentrated in solid components.

Still a further object ofthe invention is to remove or dischargevcombustion gases enriched or concentrated' in or mixed with solidcomponents from a part of the interior cylindrical wall surface of thechamber at a point in the vicinity of and-viewed in the direction of lowof the gas Whirl-before the main exhaust.

A further object of the invention is to treat the gas thus discharged inany of the following alternative ways:

1. The gas together with its contents of solid components is conductedback to a part of the combustion chamber which-viewed in the owingdirection of the combustion gas through the chamber-is situated beforethat part from which the gas is discharged. This process is particularlysuitable to be used in the case when the solid components, to asubstantial extent at least, consist of particles of fuel not completelyburnt. In this way I gain the advantage that said particles are forcedagain to pass through the chamber and then will be subjected to completeand final combustion.

2. The gas together with its contents of solid compounds is caused topass through a separator, for instance of the cyclone type, in whichsaid solid particles are separated rice from the gas and continually orperiodically removed from the system, while the gas thus puried from thesaid components is discharged from the separator and can be utilized forsome purpose, for instance heating. Alternatively the puried gas canheat the same contrivance as that heated by means of the gases passingthrough the main exhaust. 'lhis method is especially suitable for usewhen burning fuel concentrated in ashes, for instance waste sulphitelye. At the same time the ashes are removed from the system.

3. The gas purified from solid components, preferably in the same Way asin the case 2, is returned to the combustion chamber 'at a part thereoflocated at least in the vicinity of the place, at which the fuel wasinitially introduced. This method is particularly suitable to be used attiring with hydrousfuel rich in ashes, for instance waste sulphite lyeso as to elect a high temperature in thevdrying zone of the combustionchamber at the same time as separation of ashes is effected.

Some embodiments of the invention are shown diagram-V matically in theaccompanying drawings, in which Fig. l is a cross-section of anarrangement according to the invention on the line I-I of Fig. 2.

Fig. 2 is a side view of the same arrangement on the line II-II of Fig.l, some parts being sectioned.

` Fig. 3 shows a side view of a modified arrangement on a smaller scale,

Fig. 4 is a plan view of the same modification,

Fig. 5 is a si'de view of still another modification connected to thereplace of a boiler, and

Fig. 6 is a view in transverse section taken on the line 6-6 of Fig. 5.

Figures l and 2 are intended to illustrate the alternative case laforesaid, while Figures 3 and 4 illustrate case 2 and Fig. 5 case 3.

As will appear from Figures l and 2 the approximately cylindricalcombustion chamber 1 is of the whirlY chamber type and hasone or moreinlets 2 forY introducing com-y bustion air tangentially to its interiorcylindrical wall surface, and one or more main exhausts 3 for thedischarge of combustion gases preferably in axial directiom the mainexhaust or exhausts having a cross sectional area, as shown in thedrawings, which is restricted in relation to the cross sectional area ofthe adjacent part of the combustion chamber. The fuel which can consistof evaporated sulphite lye but `also of a uid sulphite lye,

for instance, is injected into the combustion chamber in exhaust 3 withan inlet 7 to the chamber also preferably-` tangential. Viewed in theaxial direction of the chamber said inlet 7 is situated farther awayfrom the exhaust 3 than the outlet 6. A tube for gas, air or steam canopen into the inlet 7 or at some other point of the duct 5.

During the operation the combustion air together with the combustiongases generated will flow on a helical path through the chamber from theinlet 2 to ythe main exhaust 3. The Whirl of gases establishes a certainpressure effect at the outlet 6, and a relative sucking etfect at theinlet 7, so that the combustion gases enriched in solid particles willbe sucked through the duct 5 from the outlet 6 into the chamber at theinlet 7. This sucking effect can be intensified by means of a flow ofgas, steam, or air, which at a relatively great speed is blown into theinlet 7 through the tube 8. The liquid fuel injected in the form ofdrops or a spray through the nozzle 4 is dried in the chamber 1 so as toforni grains or 'a powder under the influence of the heat radiated fromthe Walls of the chamber and from the burning particles of fuel. Theseparticles in the form of grains or powder are caught by the air-gaswhirl, ignited, and burnt in the state of grainsV or powder. Under theinfluence of the cenl Ytrifugal force the particles Vare carried in thedirection towards the interior cylindrical-surface of the chamber and 7so as to be subjected Yto complete-combustion duringV their renewedpassage through the chamber; 1. Preferably, the inlet 7 opens in' or atthe part, Where the new fuel Yjust introduced into the chamber'l iscaused to dry and/or be'ignited. VThe duct 5 can be built in or enclosedinto 'the wall of the chamber 1, if desired, and a pump can be arrangedinstead of the tube 8.

According to Figures 3 and 4 the gases concentrated or enriched in solidcomponents are conducted from the Vtangential outlet 6 to Va cyclone 9or some other separator, in which the solid components are separatedYfrom the gases, and carried away from the system through va bottomoutlet 10,' while the gases puriiied from said components are returnedthrough the duct 5 to a place in the combustion chamber nearer tothefuel nozzle 4 than to Vthe outlet 6. In thatway also the particlescarried away through the outlet 6 are separated through the cyclone 9.

Fig. 5 diagrammatically shows an embodiment according to which thecombustion gases concentrated or enriched in solid particles andescaping 'through th'e koutlet 6-V (not shown) after separation in thecyclone 9 'are discharged through a tube 12,1whichpreferably opens intoan :inlet 13 in the same lire place 14 (for instancea boiler) as themain exhaust from the chamber 1so that the contents of heat of allcombustion'gases generated in the chamber willV be utilized in said tireplace. This is also the case in the embodiments according to Figures1-4, thoughin these cases the'gases discharged through the outlet 6first* are' returned.l However, the tube 12 can alternatively alsoibeconnected to some other contrivance for the utilization or the heat ofthe gases. Y

According to an 'alternative embodiment two or Vmore return ducts'S canbe arranged, for instance if the combustion chamber-is provided withmeans for the introduction of fuel'in its middle part between the endseach of which has a main exhaust. Each duct will then return the gasenriched n solid particles from Va place inthe vicinity of the end partto `a place nearer to the injection means of fuel. If on the other handthe'main exhaust is f arranged at the middle part of the chamber and theintro- The invention is not restricted to the particular embodi-` mentsnow described which. are to be regarded as being illustrative but notlimiting.

What I claim is:

l. InV a combustion process for using fuel which yields solid componentsof combustion', the steps of 'passing the fuel and air into oneend Vof aywhirl type combustion chamber having an axial mainY exhaust at its;other end, Y causing the fuel to ignite and the ignited fuel, air Vand Ycombustion products to fiow'in a helical path .toward the' main exhaust,thereby causing the peripherahlayervof gas nearest the interior surfaceof the chamberr'to'become enriched, under the inuence of centrifugalforce, with solid components, tangentially withdrawing theY enrichedgases fromthe periphery of the helical ow path in the Vicinity of and inadvance of the main exhaust, sepa-V rating the solid components from thewithdrawn enriched gases externally of the combustion'chamber forremoval from the combustion process, and passing the remainingcombustion gases in the combuston'chamber through the main exhaust forheating purposes, and passing the gases from which Vthe solids'components have been separated into the same heat consumingcontrivance.

2. An arrangement for the combustion of fuelresulting in solidlcomponents of combustion, comprising in combination an elongatedjcombustion' chamberof the" whirl type having at least'onerestricted'main-exhaustvfor combustion gases at one end, means definingat least one tangential subsidiary outlet at the interior wallyofthechamber in the-vicinity of the restricted main exhaust for gasesenriched in solid fuelcomponents'due Vto centrifugal force, means forinjecting the Vfuel and air at the opposite.

end of therchamber to cause gasesfand solid components to stream throughthe chamber in Va helical path along the interior wall of the chamber tosaid subsidiary outlet and the main exhaust, a separator outside thefurnacefor separating solid components from, the gases enriched thereby,a duct connection between the subsidiary outlet and the separatorfor'conducting the gases enriched with solid components to theseparator, and a discharge outlet from the separator for said gasesfromwhich the solid components have Vbeen extracted,v rst meansto'connect the discharge outlet of the separator to a heat'consurni'ngcontrivance and secondmeans to connect the' main exhaust of the furnaceto the' heat consuming contrivance.

, References Cited in the iler'of this patentVV UNITED STATES PATENTS Yi' Aug.,29, .1922',

